1. The problem statement, all variables and given/known data M1 has a mass of 6.510 kg. It is on a horizontal surface, connected by a light string to a hook. Mass M2 can be increased smoothly by adding masses little at a time. The pulley has a negligible mass and no friction. When M2 is 3.281 kg it begins to accelerate downwards at a rate of 2.241 m/s2. Calculate (mu_s -mu_ k) for M1 on the surface. 2. Relevant equations mu_s=(f_s)max/n mu_k=f_k/n 3. The attempt at a solution I really am unsure how to go about this problem. If someone could please guide me through it that would be greatly appreciated!